Help::Auto-Download

When the slider is in the ON position clicking the download link will download the craft and open the download tab so show you more info

When the slider is in the OFF position clicking the download link will just open the download tab without downloading the craft

erm....why?
Once you've downloaded a craft the slider will automatically move to the OFF position, so you can then open the download tab without re-downloading the craft each time.
If you want to re-download the craft there will be a link in the download tab

It also acts as a visual que to remind you which craft you've already downloaded, if it's in the OFF position (red) you've already downloaded the craft.
As you are not logged in it will only remember what craft you've downloaded in this session.
Login
if you want KerbalX to remember your downloads between sessions.

Development history

[Origin of CNA series]

The Combined Nuclear-propulsion Aircraft series aims to create SSTOs with pre-1.0 performance.

With (personally) welcomed nerfing of turb-OP-jets, SSTOs of post-1.0 era have generally inferior performance. Now, creating a SSTO with at least 2km/s of dV on orbit must include nuclear propulsion system. But this presents another problem as LV-N has terrible TWR. This rules out high performance, LF-only SSTOs from emerging. To deal with a wide gap of safe transition speed - 200~300m/s between high TWR (RAPIER) to low TWR (nuclear) - one must use RAPIER’s closed cycle mode for a while. This resulted in the above-mentioned naming of my series.

All CNA series crafts have ascent profile embedded into in-game craft description for convenience.

[CNA-3IR Revenant]

Previous experiment of equipping Mk 2 sized SSTO with new 1.25m ISRU suite resulted in CNA-2IR Raven. But due to limited potential of the Ascender airframe, it had marginal dV capacity of 1.7km/s and below-average ISRU suite. So what was my next logical step? Employing a more powerful SSTO, the CNA-3 Ambassador.

The Revenant is ISRU Refuel variant of the Ambassador. Commonly referred as SCR unit, the Revenant has 5x Drill-o-Matic Jr. ore harvesters thanks to improved performance of the Ambassador airframe. Compared with the Raven, this allows 2.5x faster ore excavation. It also sports 2x ore storage capacity, requiring less user input.

A common problem with the Raven was its chronic shortage of electricity. For this, 2x Gigantor XL solar panels were installed in stretched service bay along with twofold increase in EC storage.

The increased operational weight, even with reduction in initial monopropellant capacity, means the Revenant’s ascent profile to be inefficient just like the Ascender’s. This is irrelevant, as the Revenant is primarily operated unmanned and you’ll get refueled anyway.

Trivia

I don’t like calling my SCR units single-stage-to-anywhere or SSTA. This is due to the fact that SCR units are strictly used for surface-to-mothership refuel missions (and in some cases, emergency refuel missions from Minmus to Kerbin), meaning they do not operate on their own for extended period of time.